Backward compatible head for quasi-static tilted reading and/or recording

ABSTRACT

The present invention, in some embodiments, relates to magnetic heads having modules with arrays of transducers able to read and/or write while the arrays are positioned at different angles relative to a magnetic medium, thereby enabling reading and/or writing in more than one data storage format. An apparatus according to one embodiment includes at least two modules, each of the modules having an array of N+1 transducers. Axes of the arrays are oriented about parallel to each other. N of the N+1 transducers of a first array of a first of the modules are about aligned with N of the N+1 transducers of a second array of a second of the modules when the axes of the arrays are tilted at a first angle between about 0.1° and about 10°.

BACKGROUND

The present invention relates to data storage systems, and moreparticularly, this invention relates to modules having arrays oftransducers able to read and/or write while the arrays are positioned atdifferent angles relative to a magnetic medium, thereby enabling readingand/or writing in more than one data storage format.

In magnetic storage systems, data is read from and written onto magneticrecording media utilizing magnetic transducers. Data is written on themagnetic recording media by moving a magnetic recording transducer to aposition over the media where the data is to be stored. The magneticrecording transducer then generates a magnetic field, which encodes thedata into the magnetic media. Data is read from the media by similarlypositioning the magnetic read transducer and then sensing the magneticfield of the magnetic media. Read and write operations may beindependently synchronized with the movement of the media to ensure thatthe data can be read from and written to the desired location on themedia.

An important and continuing goal in the data storage industry is that ofincreasing the density of data stored on a medium. For tape storagesystems, that goal has led to increasing the track and linear bitdensity on recording tape, and decreasing the thickness of the magnetictape medium. However, the development of small footprint, higherperformance tape drive systems has created various problems in thedesign of a tape head assembly for use in such systems.

In a tape drive system, magnetic tape is moved over the surface of thetape head at high speed. Usually the tape head is designed to minimizethe spacing between the head and the tape. The spacing between themagnetic head and the magnetic tape is crucial and so goals in thesesystems are to have the recording gaps of the transducers, which are thesource of the magnetic recording flux in near contact with the tape toeffect writing sharp transitions, and to have the read elements in nearcontact with the tape to provide effective coupling of the magneticfield from the tape to the read elements.

The quantity of data stored on a magnetic tape may be increased byincreasing the number of data tracks across the tape. More tracks aremade possible by reducing feature sizes of the readers and writers, suchas by using thin-film fabrication techniques and MR sensors. However,for various reasons, the feature sizes of readers and writers cannot bearbitrarily reduced, and so factors such as lateral tape motiontransients and tape lateral expansion and contraction (e.g.,perpendicular to the direction of tape travel) must be balanced withreader/writer sizes that provide acceptable written tracks and readbacksignals. One issue limiting areal density is misregistration caused bytape lateral expansion and contraction. Tape width can vary by up toabout 0.1% due to expansion and contraction caused by changes inhumidity, tape tension, temperature, aging, etc. This is often referredto as tape dimensional stability (TDS).

If the tape is written in one environment and then read back in another,the TDS may prevent the spacing of the tracks on the tape from preciselymatching the spacing of the reading elements during readback. In currentproducts, the change in track spacing due to TDS is small compared tothe size of the written tracks and is part of the tracking budget thatis considered when designing a product. As the tape capacity increasesover time, tracks are becoming smaller and TDS is becoming anincreasingly larger portion of the tracking budget and this is alimiting factor for growing areal density.

BRIEF SUMMARY

An apparatus according to one embodiment includes at least two modules,each of the modules having an array of N+1 transducers. An axis of eacharray is defined between opposite ends thereof. The axes of the arraysare oriented about parallel to each other. N of the N+1 transducers of afirst array of a first of the modules are about aligned with N of theN+1 transducers of a second array of a second of the modules when theaxes of the arrays are positioned towards a first position, the firstposition being characterized by the axes of the arrays each beingoriented at a first angle between about 0.1° and about 10° relative to aline oriented perpendicular to an intended direction of tape travelthereacross. N+1 of the N+1 transducers of the first array are aboutaligned with N+1 of the N+1 transducers of the second array when theaxes of the arrays are positioned towards a second position, the axes ofthe arrays each being oriented at a second angle that is smaller thanthe first angle relative to the line oriented perpendicular to theintended direction of tape travel.

Any of these embodiments may be implemented in a magnetic data storagesystem such as a tape drive system, which may include a magnetic head, adrive mechanism for passing a magnetic medium (e.g., recording tape)over the magnetic head, and a controller electrically coupled to themagnetic head.

Other aspects and embodiments of the present invention will becomeapparent from the following detailed description, which, when taken inconjunction with the drawings, illustrate by way of example theprinciples of the invention.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1A is a schematic diagram of a simplified tape drive systemaccording to one embodiment.

FIG. 1B is a schematic diagram of a tape cartridge according to oneembodiment.

FIG. 2 illustrates a side view of a flat-lapped, bi-directional,two-module magnetic tape head according to one embodiment.

FIG. 2A is a tape bearing surface view taken from Line 2A of FIG. 2.

FIG. 2B is a detailed view taken from Circle 2B of FIG. 2A.

FIG. 2C is a detailed view of a partial tape bearing surface of a pairof modules.

FIG. 3 is a partial tape bearing surface view of a magnetic head havinga write-read-write configuration.

FIG. 4 is a partial tape bearing surface view of a magnetic head havinga read-write-read configuration.

FIG. 5 is a side view of a magnetic tape head with three modulesaccording to one embodiment where the modules all generally lie alongabout parallel planes.

FIG. 6 is a side view of a magnetic tape head with three modules in atangent (angled) configuration.

FIG. 7 is a side view of a magnetic tape head with three modules in anoverwrap configuration.

FIGS. 8A-8C are partial top-down views of one module of a magnetic tapehead according to one embodiment.

FIGS. 9A-9C are partial top-down views of one module of a magnetic tapehead according to one embodiment.

FIGS. 10A-10C are partial top-down views of an apparatus having twomodules, according to one embodiment.

FIG. 10D is a diagram of the system having the apparatus of FIGS.10A-10B.

FIG. 11 is a partial top-down view of an apparatus having three modules,according to one embodiment.

FIG. 12A is a diagram of a tape with shingled tracks written in anon-serpentine fashion according to one embodiment.

FIG. 12B is a diagram of a tape with shingled tracks written in aserpentine fashion according to one embodiment.

DETAILED DESCRIPTION

The following description is made for the purpose of illustrating thegeneral principles of the present invention and is not meant to limitthe inventive concepts claimed herein. Further, particular featuresdescribed herein can be used in combination with other describedfeatures in each of the various possible combinations and permutations.

Unless otherwise specifically defined herein, all terms are to be giventheir broadest possible interpretation including meanings implied fromthe specification as well as meanings understood by those skilled in theart and/or as defined in dictionaries, treatises, etc.

It must also be noted that, as used in the specification and theappended claims, the singular forms “a,” “an” and “the” include pluralreferents unless otherwise specified.

The following description discloses several preferred embodiments ofmagnetic storage systems having data transducers compatible withmultiple data storage formats, as well as operation and/or componentparts thereof. In various embodiments herein, the transducer arrays mayread and/or write data while being oriented at different angles relativeto a magnetic tape, thereby enabling compatibility with different datastorage formats. Additionally, by enabling selective rotation of thetransducers relative to a magnetic tape being written to and/or havingdata read therefrom, some embodiments herein are preferably also able tocompensate for varying conditions of the magnetic tape being written toand/or having data read therefrom, as will be discussed in furtherdetail below.

In one general embodiment, an apparatus includes at least two modules,each of the modules having an array of N+1 transducers. An axis of eacharray is defined between opposite ends thereof. The axes of the arraysare oriented about parallel to each other. N of the N+1 transducers of afirst array of a first of the modules are about aligned with N of theN+1 transducers of a second array of a second of the modules when theaxes of the arrays are positioned towards a first position, the firstposition being characterized by the axes of the arrays each beingoriented at a first angle between about 0.10 and about 10° relative to aline oriented perpendicular to an intended direction of tape travelthereacross. N+1 of the N+1 transducers of the first array are aboutaligned with N+1 of the N+1 transducers of the second array when theaxes of the arrays are positioned towards a second position, the axes ofthe arrays each being oriented at a second angle that is smaller thanthe first angle relative to the line oriented perpendicular to theintended direction of tape travel.

FIG. 1A illustrates a simplified tape drive 100 of a tape-based datastorage system, which may be employed in the context of the presentinvention. While one specific implementation of a tape drive is shown inFIG. 1A, it should be noted that the embodiments described herein may beimplemented in the context of any type of tape drive system.

As shown, a tape supply cartridge 120 and a take-up reel 121 areprovided to support a tape 122. One or more of the reels may form partof a removable cartridge and are not necessarily part of the system 100.The tape drive, such as that illustrated in FIG. 1A, may further includedrive motor(s) to drive the tape supply cartridge 120 and the take-upreel 121 to move the tape 122 over a tape head 126 of any type. Suchhead may include an array of readers, writers, or both.

Guides 125 guide the tape 122 across the tape head 126. Such tape head126 is in turn coupled to a controller 128 via a cable 130. Thecontroller 128, may be or include a processor and/or any logic forcontrolling any subsystem of the drive 100. For example, the controller128 typically controls head functions such as servo following, datawriting, data reading, etc. The controller 128 may operate under logicknown in the art, as well as any logic disclosed herein. The controller128 may be coupled to a memory 136 of any known type, which may storeinstructions executable by the controller 128. Moreover, the controller128 may be configured and/or programmable to perform or control some orall of the methodology presented herein. Thus, the controller may beconsidered configured to perform various operations by way of logicprogrammed into a chip; software, firmware, or other instructions beingavailable to a processor; etc. and combinations thereof.

The cable 130 may include read/write circuits to transmit data to thehead 126 to be recorded on the tape 122 and to receive data read by thehead 126 from the tape 122. An actuator 132 controls position of thehead 126 relative to the tape 122.

An interface 134 may also be provided for communication between the tapedrive 100 and a host (integral or external) to send and receive the dataand for controlling the operation of the tape drive 100 andcommunicating the status of the tape drive 100 to the host, all as willbe understood by those of skill in the art.

FIG. 1B illustrates an exemplary tape cartridge 150 according to oneembodiment. Such tape cartridge 150 may be used with a system such asthat shown in FIG. 1A. As shown, the tape cartridge 150 includes ahousing 152, a tape 122 in the housing 152, and a nonvolatile memory 156coupled to the housing 152. In some embodiments, the nonvolatile memory156 may be embedded inside the housing 152, as shown in FIG. 1B. In moreembodiments, the nonvolatile memory 156 may be attached to the inside oroutside of the housing 152 without modification of the housing 152. Forexample, the nonvolatile memory may be embedded in a self-adhesive label154. In one preferred embodiment, the nonvolatile memory 156 may be aFlash memory device, ROM device, etc., embedded into or coupled to theinside or outside of the tape cartridge 150. The nonvolatile memory isaccessible by the tape drive and the tape operating software (the driversoftware), and/or other device.

By way of example, FIG. 2 illustrates a side view of a flat-lapped,bi-directional, two-module magnetic tape head 200 which may beimplemented in the context of the present invention. As shown, the headincludes a pair of bases 202, each equipped with a module 204, and fixedat a small angle α with respect to each other. The bases may be“U-beams” that are adhesively coupled together. Each module 204 includesa substrate 204A and a closure 204B with a thin film portion, commonlyreferred to as a “gap” in which the readers and/or writers 206 areformed. In use, a tape 208 is moved over the modules 204 along a media(tape) bearing surface 209 in the manner shown for reading and writingdata on the tape 208 using the readers and writers. The wrap angle θ ofthe tape 208 at edges going onto and exiting the flat media supportsurfaces 209 are usually between about 0.1 degree and about 3 degrees.

The substrates 204A are typically constructed of a wear resistantmaterial, such as a ceramic. The closures 204B made of the same orsimilar ceramic as the substrates 204A.

The readers and writers may be arranged in a piggyback or mergedconfiguration. An illustrative piggybacked configuration comprises a(magnetically inductive) writer transducer on top of (or below) a(magnetically shielded) reader transducer (e.g., a magnetoresistivereader, etc.), wherein the poles of the writer and the shields of thereader are generally separated. An illustrative merged configurationcomprises one reader shield in the same physical layer as one writerpole (hence, “merged”). The readers and writers may also be arranged inan interleaved configuration. Alternatively, each array of channels maybe readers or writers only. Any of these arrays may contain one or moreservo track readers for reading servo data on the medium.

FIG. 2A illustrates the tape bearing surface 209 of one of the modules204 taken from Line 2A of FIG. 2. A representative tape 208 is shown indashed lines. The module 204 is preferably long enough to be able tosupport the tape as the head steps between data bands.

In this example, the tape 208 includes 4 to 22 data bands, e.g., with 8data bands and 9 servo tracks 210, as shown in FIG. 2A on a one-halfinch wide tape 208. The data bands are defined between servo tracks 210.Each data band may include a number of data tracks, for example 1024data tracks (not shown). During read/write operations, the readersand/or writers 206 are positioned to specific track positions within oneof the data bands. Outer readers, sometimes called servo readers, readthe servo tracks 210. The servo signals are in turn used to keep thereaders and/or writers 206 aligned with a particular set of tracksduring the read/write operations.

FIG. 2B depicts a plurality of readers and/or writers 206 formed in agap 218 on the module 204 in Circle 2B of FIG. 2A. As shown, the arrayof readers and writers 206 includes, for example, 16 writers 214, 16readers 216 and two servo readers 212, though the number of elements mayvary. Illustrative embodiments include 8, 16, 32, 40, and 64 activereaders and/or writers 206 per array, and alternatively interleaveddesigns having odd numbers of reader or writers such as 17, 25, 33, etc.An illustrative embodiment includes 32 readers per array and/or 32writers per array, where the actual number of transducer elements couldbe greater, e.g., 33, 34, etc. This allows the tape to travel moreslowly, thereby reducing speed-induced tracking and mechanicaldifficulties and/or execute fewer “wraps” to fill or read the tape.While the readers and writers may be arranged in a piggybackconfiguration as shown in FIG. 2B, the readers 216 and writers 214 mayalso be arranged in an interleaved configuration. Alternatively, eacharray of readers and/or writers 206 may be readers or writers only, andthe arrays may contain one or more servo readers 212. As noted byconsidering FIGS. 2 and 2A-B together, each module 204 may include acomplementary set of readers and/or writers 206 for such things asbi-directional reading and writing, read-while-write capability,backward compatibility, etc.

FIG. 2C shows a partial tape bearing surface view of complimentarymodules of a magnetic tape head 200 according to one embodiment. In thisembodiment, each module has a plurality of read/write (R/W) pairs in apiggyback configuration formed on a common substrate 204A and anoptional electrically insulative layer 236. The writers, exemplified bythe write transducer 214 and the readers, exemplified by the readtransducer 216, are aligned parallel to an intended direction of travelof a tape medium thereacross to form an R/W pair, exemplified by the R/Wpair 222. Note that the intended direction of tape travel is sometimesreferred to herein as the direction of tape travel, and such terms maybe used interchangeable. Such direction of tape travel may be inferredfrom the design of the system, e.g., by examining the guides; observingthe actual direction of tape travel relative to the reference point;etc. Moreover, in a system operable for bi-direction reading and/orwriting, the direction of tape travel in both directions is typicallyparallel and thus both directions may be considered equivalent to eachother.

Several R/W pairs 222 may be present, such as 8, 16, 32 pairs, etc. TheR/W pairs 222 as shown are linearly aligned in a direction generallyperpendicular to a direction of tape travel thereacross. However, thepairs may also be aligned diagonally, etc. Servo readers 212 arepositioned on the outside of the array of R/W pairs, the function ofwhich is well known.

Generally, the magnetic tape medium moves in either a forward or reversedirection as indicated by arrow 220. The magnetic tape medium and headassembly 200 operate in a transducing relationship in the mannerwell-known in the art. The piggybacked MR head assembly 200 includes twothin-film modules 224 and 226 of generally identical construction.

Modules 224 and 226 are joined together with a space present betweenclosures 204B thereof (partially shown) to form a single physical unitto provide read-while-write capability by activating the writer of theleading module and reader of the trailing module aligned with the writerof the leading module parallel to the direction of tape travel relativethereto. When a module 224, 226 of a piggyback head 200 is constructed,layers are formed in the gap 218 created above an electricallyconductive substrate 204A (partially shown), e.g., of AlTiC, ingenerally the following order for the R/W pairs 222: an insulating layer236, a first shield 232 typically of an iron alloy such as NiFe (−), CZTor Al—Fe—Si (Sendust), a sensor 234 for sensing a data track on amagnetic medium, a second shield 238 typically of a nickel-iron alloy(e.g., ˜80/20 at % NiFe, also known as permalloy), first and secondwriter pole tips 228, 230, and a coil (not shown). The sensor may be ofany known type, including those based on MR, GMR, AMR, tunnelingmagnetoresistance (TMR), etc.

The first and second writer poles 228, 230 may be fabricated from highmagnetic moment materials such as ˜45/55 NiFe. Note that these materialsare provided by way of example only, and other materials may be used.Additional layers such as insulation between the shields and/or poletips and an insulation layer surrounding the sensor may be present.Illustrative materials for the insulation include alumina and otheroxides, insulative polymers, etc.

The configuration of the tape head 126 according to one embodimentincludes multiple modules, preferably three or more. In awrite-read-write (W-R-W) head, outer modules for writing flank one ormore inner modules for reading. Referring to FIG. 3, depicting a W-R-Wconfiguration, the outer modules 252, 256 each include one or morearrays of writers 260. The inner module 254 of FIG. 3 includes one ormore arrays of readers 258 in a similar configuration. Variations of amulti-module head include a R-W-R head (FIG. 4), a R-R-W head, a W-W-Rhead, etc. In yet other variations, one or more of the modules may haveread/write pairs of transducers. Moreover, more than three modules maybe present. In further embodiments, two outer modules may flank two ormore inner modules, e.g., in a W-R-R-W, a R-W-W-R arrangement, etc. Forsimplicity, a W-R-W head is used primarily herein to exemplifyembodiments of the present invention. One skilled in the art apprisedwith the teachings herein will appreciate how permutations of thepresent invention would apply to configurations other than a W-R-Wconfiguration.

FIG. 5 illustrates a magnetic head 126 according to one embodiment ofthe present invention that includes first, second and third modules 302,304, 306 each having a tape bearing surface 308, 310, 312 respectively,which may be flat, contoured, etc. Note that while the term “tapebearing surface” appears to imply that the surface facing the tape 315is in physical contact with the tape bearing surface, this is notnecessarily the case. Rather, only a portion of the tape may be incontact with the tape bearing surface, constantly or intermittently,with other portions of the tape riding (or “flying”) above the tapebearing surface on a layer of air, sometimes referred to as an “airbearing”. The first module 302 will be referred to as the “leading”module as it is the first module encountered by the tape in a threemodule design for tape moving in the indicated direction. The thirdmodule 306 will be referred to as the “trailing” module. The trailingmodule follows the middle module and is the last module seen by the tapein a three module design. The leading and trailing modules 302, 306 arereferred to collectively as outer modules. Also note that the outermodules 302, 306 will alternate as leading modules, depending on thedirection of travel of the tape 315.

In one embodiment, the tape bearing surfaces 308, 310, 312 of the first,second and third modules 302, 304, 306 lie on about parallel planes(which is meant to include parallel and nearly parallel planes, e.g.,between parallel and tangential as in FIG. 6), and the tape bearingsurface 310 of the second module 304 is above the tape bearing surfaces308, 312 of the first and third modules 302, 306. As described below,this has the effect of creating the desired wrap angle α₂ of the taperelative to the tape bearing surface 310 of the second module 304.

Where the tape bearing surfaces 308, 310, 312 lie along parallel ornearly parallel yet offset planes, intuitively, the tape should peel offof the tape bearing surface 308 of the leading module 302. However, thevacuum created by the skiving edge 318 of the leading module 302 hasbeen found by experimentation to be sufficient to keep the tape adheredto the tape bearing surface 308 of the leading module 302. The trailingedge 320 of the leading module 302 (the end from which the tape leavesthe leading module 302) is the approximate reference point which definesthe wrap angle α₂ over the tape bearing surface 310 of the second module304. The tape stays in close proximity to the tape bearing surface untilclose to the trailing edge 320 of the leading module 302. Accordingly,read and/or write elements 322 may be located near the trailing edges ofthe outer modules 302, 306. These embodiments are particularly adaptedfor write-read-write applications.

A benefit of this and other embodiments described herein is that,because the outer modules 302, 306 are fixed at a determined offset fromthe second module 304, the inner wrap angle α₂ is fixed when the modules302, 304, 306 are coupled together or are otherwise fixed into a head.The inner wrap angle α₂ is approximately tan⁻¹(δ/W) where δ is theheight difference between the planes of the tape bearing surfaces 308,310 and W is the width between the opposing ends of the tape bearingsurfaces 308, 310. An illustrative inner wrap angle α₂ is in a range ofabout 0.3° to about 1.1°, though can be any angle required by thedesign.

Beneficially, the inner wrap angle α₂ on the side of the module 304receiving the tape (leading edge) will be larger than the inner wrapangle α₃ on the trailing edge, as the tape 315 rides above the trailingmodule 306. This difference is generally beneficial as a smaller α₃tends to oppose what has heretofore been a steeper exiting effectivewrap angle.

Note that the tape bearing surfaces 308, 312 of the outer modules 302,306 are positioned to achieve a negative wrap angle at the trailing edge320 of the leading module 302. This is generally beneficial in helpingto reduce friction due to contact with the trailing edge 320, providedthat proper consideration is given to the location of the crowbar regionthat forms in the tape where it peels off the head. This negative wrapangle also reduces flutter and scrubbing damage to the elements on theleading module 302. Further, at the trailing module 306, the tape 315flies over the tape bearing surface 312 so there is virtually no wear onthe elements when tape is moving in this direction. Particularly, thetape 315 entrains air and so will not significantly ride on the tapebearing surface 312 of the third module 306 (some contact may occur).This is permissible, because the leading module 302 is writing while thetrailing module 306 is idle.

Writing and reading functions are performed by different modules at anygiven time. In one embodiment, the second module 304 includes aplurality of data and optional servo readers 331 and no writers. Thefirst and third modules 302, 306 include a plurality of writers 322 andno data readers, with the exception that the outer modules 302, 306 mayinclude optional servo readers. The servo readers may be used toposition the head during reading and/or writing operations. The servoreader(s) on each module are typically located towards the end of thearray of readers or writers.

By having only readers or side by side writers and servo readers in thegap between the substrate and closure, the gap length can besubstantially reduced. Typical heads have piggybacked readers andwriters, where the writer is formed above each reader. A typical gap is20-35 microns. However, irregularities on the tape may tend to droopinto the gap and create gap erosion. Thus, the smaller the gap is thebetter. The smaller gap enabled herein exhibits fewer wear relatedproblems.

In some embodiments, the second module 304 has a closure, while thefirst and third modules 302, 306 do not have a closure. Where there isno closure, preferably a hard coating is added to the module. Onepreferred coating is diamond-like carbon (DLC).

In the embodiment shown in FIG. 5, the first, second, and third modules302, 304, 306 each have a closure 332, 334, 336, which extends the tapebearing surface of the associated module, thereby effectivelypositioning the read/write elements away from the edge of the tapebearing surface. The closure 332 on the second module 304 can be aceramic closure of a type typically found on tape heads. The closures334, 336 of the first and third modules 302, 306, however, may beshorter than the closure 332 of the second module 304 as measuredparallel to a direction of tape travel over the respective module. Thisenables positioning the modules closer together. One way to produceshorter closures 334, 336 is to lap the standard ceramic closures of thesecond module 304 an additional amount. Another way is to plate ordeposit thin film closures above the elements during thin filmprocessing. For example, a thin film closure of a hard material such asSendust or nickel-iron alloy (e.g., 45/55) can be formed on the module.

With reduced-thickness ceramic or thin film closures 334, 336 or noclosures on the outer modules 302, 306, the write-to-read gap spacingcan be reduced to less than about 1 mm, e.g., about 0.75 mm, or 50% lessthan commonly-used LTO tape head spacing. The open space between themodules 302, 304, 306 can still be set to approximately 0.5 to 0.6 mm,which in some embodiments is ideal for stabilizing tape motion over thesecond module 304.

Depending on tape tension and stiffness, it may be desirable to anglethe tape bearing surfaces of the outer modules relative to the tapebearing surface of the second module. FIG. 6 illustrates an embodimentwhere the modules 302, 304, 306 are in a tangent or nearly tangent(angled) configuration. Particularly, the tape bearing surfaces of theouter modules 302, 306 are about parallel to the tape at the desiredwrap angle α₂ of the second module 304. In other words, the planes ofthe tape bearing surfaces 308, 312 of the outer modules 302, 306 areoriented at about the desired wrap angle α₂ of the tape 315 relative tothe second module 304. The tape will also pop off of the trailing module306 in this embodiment, thereby reducing wear on the elements in thetrailing module 306. These embodiments are particularly useful forwrite-read-write applications. Additional aspects of these embodimentsare similar to those given above.

Typically, the tape wrap angles may be set about midway between theembodiments shown in FIGS. 5 and 6.

FIG. 7 illustrates an embodiment where the modules 302, 304, 306 are inan overwrap configuration. Particularly, the tape bearing surfaces 308,312 of the outer modules 302, 306 are angled slightly more than the tape315 when set at the desired wrap angle α₂ relative to the second module304. In this embodiment, the tape does not pop off of the trailingmodule, allowing it to be used for writing or reading. Accordingly, theleading and middle modules can both perform reading and/or writingfunctions while the trailing module can read any just-written data.Thus, these embodiments are preferred for write-read-write,read-write-read, and write-write-read applications. In the latterembodiments, closures should be wider than the tape canopies forensuring read capability. The wider closures may require a widergap-to-gap separation. Therefore a preferred embodiment has awrite-read-write configuration, which may use shortened closures thatthus allow closer gap-to-gap separation.

Additional aspects of the embodiments shown in FIGS. 6 and 7 are similarto those given above.

A 32 channel version of a multi-module head 126 may use cables 350having leads on the same or smaller pitch as current 16 channelpiggyback LTO modules, or alternatively the connections on the modulemay be organ-keyboarded for a 50% reduction in cable span. Over-under,writing pair unshielded cables may be used for the writers, which mayhave integrated servo readers.

The outer wrap angles α₁ may be set in the drive, such as by guides ofany type known in the art, such as adjustable rollers, slides, etc. oralternatively by outriggers, which are integral to the head. Forexample, rollers having an offset axis may be used to set the wrapangles. The offset axis creates an orbital arc of rotation, allowingprecise alignment of the wrap angle α₁.

To assemble any of the embodiments described above, conventional u-beamassembly can be used. Accordingly, the mass of the resultant head may bemaintained or even reduced relative to heads of previous generations. Inother embodiments, the modules may be constructed as a unitary body.Those skilled in the art, armed with the present teachings, willappreciate that other known methods of manufacturing such heads may beadapted for use in constructing such heads.

As noted above, tape lateral expansion and contraction present manychallenges to increasing data track density on conventional products.Conventional products have attempted to compensate for tape lateralexpansion and contraction by controlling tape width by tension andimproving the characteristics of the media itself. However, thesemethods fail to fully cancel the tape lateral expansion and contraction,and actually lead to other problems, including tape stretch and mediacost increases, respectively.

FIGS. 8A-8C are intended to depict the effect of tape lateral expansionand contraction on transducer arrays position relative thereto, and arein no way intended to limit the invention. FIG. 5A depicts a module 800relative to the tape 802, where the tape has a nominal width. As shown,the transducers 804 are favorably aligned with the data tracks 806 onthe tape 802. However, FIG. 8B illustrates the effect of tape lateralcontraction. As shown, contraction of the tape causes the data tracks tocontract as well, and the outermost transducers 808 are positioned alongthe outer edges of the outer data tracks as a result. Moreover, FIG. 8Cdepicts the effect of tape lateral expansion. Here expansion of the tapecauses the data tracks to move farther apart, and the outermosttransducers 808 are positioned along the inner edges of the outer datatracks as a result. If the tape lateral contraction is greater than thatshown in FIG. 8B, or the tape lateral expansion is greater than thatshown in FIG. 5C, the outermost transducers 808 will cross onto adjacenttracks, thereby causing the data stored on adjacent tracks to beoverwritten during a writing operation and/or resulting in readback ofthe wrong track during a readback operation. Moreover, running effects,such as tape skew and lateral shifting may exacerbate such problems,particularly for tape having shingled data tracks.

Thus, it would be desirable to develop a tape drive system able to readand/or write tracks onto the tape in the proper position, regardless ofthe extent of tape lateral expansion and/or contraction at any giventime. Various embodiments described and/or suggested herein overcome theforegoing challenges of conventional products, by orienting at least twomodules of a tape drive system, such as by rotating, pivoting and/ortilting, thereby selectively altering the pitch of the transducers intheir arrays, as will soon become apparent.

By selectively orienting a module, the pitch of the transducers on themodule is thereby altered, preferably aligning the transducers with thetracks on a tape for a given tape lateral expansion and/or contraction.Tape contraction (shrinkage) can be dealt with by orienting a nominallynon-offset head, but tape expansion (dilation) cannot. Thus, toaccommodate both shrinkage and dilation about a “nominal,” the head mustbe statically positioned at a nominal angle of at least approximately0.1° as will be explained below. Thereafter, smaller angular adjustments(e.g., about 1° or lower, but could be more) may be made to thealready-oriented module in order to compensate for any variation of thetape lateral expansion and/or contraction, thereby keeping thetransducers aligned with tracks on the tape.

FIGS. 9A-9C illustrate representational views of the effects oforienting a module having transducer arrays. It should be noted that theangles of orientation illustrated in FIGS. 9A-9C are an exaggeration(e.g., larger than would typically be observed), and are in no wayintended to limit the invention.

Referring to FIG. 9A, the module 900 is shown relative to the tape 902,where the tape has a nominal width. As illustrated, the module 900 isoriented at an angle θ_(nom) such that the transducers 904 are favorablyaligned with the data tracks 906 on the tape 902. However, when the tape902 experiences tape lateral contraction and/or expansion, the datatracks 906 on the tape contract and/or expand as well. As a result, thetransducers on the module are no longer favorably aligned with the datatracks 906 on the tape 902.

In FIG. 9B, the tape 902 has experienced tape lateral contraction.Therefore, in a manner exemplified by FIG. 8B, the transducers 904 onthe module 900 of FIG. 9B would no longer be favorably aligned with thedata tracks 906 on the tape 902 if no adjustment were made. However, asalluded to above, smaller angular adjustments may be made to thealready-oriented module 900 in order to compensate for tape lateralcontraction. Therefore, referring again to FIG. 9B, the angle oforientation >θ_(nom) of the module 900 is further positioned at an anglegreater than θ_(nom). By increasing the angle >θ_(nom) the effectivewidth w₂ of the array of transducers decreases from the effective widthw₁ illustrated in FIG. 9A. This also translates to a reduction in theeffective pitch between the transducers, thereby realigning thetransducers along the contracted data tracks 906 on the tape 902 asshown in FIG. 9B.

On the other hand, when the tape experiences tape lateral expansion, thedata tracks on the tape expand as well. As a result, the transducers onthe module would no longer be favorably aligned with the data tracks onthe tape if no adjustments were made. With reference to FIG. 9C, thetape 902 has experienced tape lateral expansion. As a result, furtherangular adjustments may be made to the angle of orientation of themodule in order to compensate for the tape lateral expansion. Therefore,referring again to FIG. 9C, the angle of orientation <θ_(nom) of themodule 900 is reduced to an angle less than θ_(nom). By decreasing theangle of orientation <θ_(nom) the effective width w₃ of the array oftransducers 904 increases from the effective width w₁ illustrated inFIG. 9A. Moreover, reducing the effective width of the array oftransducers 904 also causes the effective pitch between the transducersto be reduced, thereby realigning the transducers along the data tracks906 on the tape 902.

In a preferred embodiment, magnetic tape systems have two or moremodules, each having an array of transducers, typically in a row.Depending on the desired embodiment, the additional rows of transducersmay allow the system to read verify during the write process, but is notlimited thereto. As mentioned above, the foregoing conventionalchallenges may be overcome, e.g., by rotating a given module about anaxis orthogonal to the plane in which its array resides (e.g., parallelto the plane of the tape bearing surface), thereby selectively alteringthe pitch of the transducers in the array.

By providing a system that compensates for tape lateral expansion and/orcontraction, various embodiments enable use of wider readers, resultingin a better signal to noise ratio (SNR), and/or smaller data tracks,resulting in a higher capacity per unit area of the media.

Furthermore, an apparatus capable of writing and/or reading data writtenin multiple data storage formats may be incorporated with any of theembodiments described above. This may preferably increase the data readand/or write performance of various embodiments presented herein byimproving compensation with tape skew, shifting, lateral contractionand/or expansion, etc. In various embodiments, compatibility withmultiple storage formats may be achieved by incorporating selectivelytiltable data transducers, e.g., as described above with reference toFIGS. 9A-9C, as will soon become apparent.

FIGS. 10A-10D depict an apparatus 1000, in accordance with oneembodiment. As an option, the present apparatus 1000 may be implementedin conjunction with features from any other embodiment listed herein,such as those described with reference to the other FIGS. Of course,however, such apparatus 1000 and others presented herein may be used invarious applications and/or in permutations which may or may not bespecifically described in the illustrative embodiments listed herein.Further, the apparatus 1000 presented herein may be used in any desiredenvironment. Thus FIGS. 10A-10D (and the other FIGS.) should be deemedto include any and all possible permutations.

Referring now to FIGS. 10A-10C, the apparatus 1000 includes a magnetichead 1050 having two modules 1002, 1004. Moreover, each of the modules1002, 1004 has an array 1006, 1008 of N+1 transducers 1010,respectively. The modules 1002, 1004 of the apparatus 1000 mayadditionally include servo transducer pairs S1, S2 as illustrated, whichmay include any type of servo transducer described and/or suggestedherein, e.g., see 212 of FIG. 2C.

Although there are only two modules in the embodiment depicted in FIGS.10A-10D, according to other embodiments, the apparatus 1000 may includeat least two modules e.g., 2, 3, 4, etc. modules, depending on thedesired embodiment. Moreover, it should be noted that the variableidentifier “N” is used in several instances herein, to more simplydesignate the final element of a series of related or similar elements.The repeated use of such variable identifiers is not meant to imply acorrelation between the sizes of such series of elements, although suchcorrelation may exist. The use of such variable identifiers does notrequire that the series of elements has the same number of elements asanother series delimited by the same variable identifier. Rather, ineach instance of use, the variable identified by “N” may hold the sameor a different value than other instances of the same variableidentifier.

For example, which is in no way intended to limit the invention, in theembodiment illustrated in FIGS. 10A-10C, there are a total of 17transducer pairs. Thus, N+1 (i.e., the total number of transducers)=17,thereby setting the value of N as 16. However, in other embodiments, theapparatus may include more or fewer transducers, thereby changing thevalue of “N” accordingly, depending on the embodiment.

With continued reference to FIGS. 10A-10C, according to a preferredembodiment, each of the transducers 1010 of the first and second arrays1006, 1008 are reader/writer pairs. Thus, each transducer pair includesa reader and a writer, thereby preferably enabling read while writecapability for the modules 1002, 1004 of the apparatus 1000. However, inanother embodiment, the transducers for each of the modules of anapparatus may include arrays of single reader and/or writer transducers,e.g., see FIG. 11. In such embodiments having arrays of singletransducers, at least three arrays may be incorporated, e.g., to enableread while write functionality as will be discussed in detail below.

With continued reference to FIGS. 10A-10C, the modules 1002, 1004 arepreferably fixed relative to each other. In view of the presentdescription, “fixed” is intended to mean constrained from a directionalmovement relative to each other such that the arrays of each maintain afixed position relative to each other. According to various embodiments,the modules may be fixed relative to each other by using rods,fasteners, adhesives, cables, wire, etc. Moreover, according todifferent embodiments, the modules are preferably fixed relative to eachother prior to being installed in the system 1000, head, etc. dependingon the desired embodiment. However, the modules are preferablyselectively orientable (e.g., tiltable and/or rotatable) as a singlestructure about a pivot point while remaining fixed relative to eachother, as will soon become apparent.

The modules 1002, 1004, are also preferably fixed such that the axes1012, 1013 of the arrays 1006, 1008 are oriented about parallel to eachother, respectively, e.g., at a relative angle of less than 0.1°. Asillustrated in FIGS. 10A-10C, the axes 1012, 1013 of each array oftransducers are defined by the dashed lines that lie between oppositeends thereof, e.g., positioned farthest apart.

As mentioned above, the modules 1002, 1004 are preferably selectivelyorientable (e.g., tiltable and/or rotatable) between a first positionand a second position, e.g., about a pivot point. Looking now to FIG.10A, in one embodiment, the modules 1002, 1004 may be oriented such thatthe axes 1012, 1013 of the arrays 1006, 1008 are oriented at a firstangle φ, relative to a line 1030 oriented perpendicular to an intendeddirection 1020 of tape travel thereacross. According to variousembodiments, the first angle φ may be between about 0.1° and about 10°,but may be higher or lower depending on the desired embodiment.

When the axes 1012, 1013 of the arrays 1006, 1008 are positioned towardsa first position (tilted), as shown in FIG. 10A, N of the N+1transducers 1010 of the first array 1006 of a first module 1002 arepreferably about aligned with N of the N+1 transducers of the secondarray 1008 of a second of the modules 1004. Furthermore, the N of theN+1 transducers 1010 of the first and second arrays 1006, 1008 arepreferably aligned within the data tracks of a tape (not shown) whenpositioned towards and/or at the first position. Thus, the N of the N+1transducers 1010 may preferably write to and/or read from Ncorresponding data tracks of a magnetic tape (e.g., see 902 and 906 ofFIGS. 9A-9C).

However, referring now to FIG. 10B, when the axes 1012, 1013 of thearrays 1006, 1008 are positioned towards a second position (vertical)and aligned approximately with line 1030, N+1 of the N+1 transducers1010 of the first array 1006 are preferably about aligned with N+1 ofthe N+1 transducers 1010 of the second array 1008. In order to achievesuch alignment, the transducers and/or modules are preferably not offsetin the crosstrack direction (orthogonal to the intended direction 1020of tape travel) when positioned towards and/or at the second position.

Furthermore, the apparatus is preferably configured to read and/or writewith the N+1 transducers when the axes 1012, 1013 of the arrays 1006,1008 are positioned towards and/or at the second position. In variousembodiments, the apparatus 1000 may use a mechanism 1014 and/or acontroller 1016 to enable reading and/or writing with the N+1 and/or Nof the N+1 transducers, depending on the desired embodiment, asdescribed in detail below with reference to FIG. 10D.

Referring still to FIGS. 10A-10B, according to preferred embodiments,the second position corresponds to the axes 1012, 1013 of the arrays1006, 1008 each being oriented at an angle that is smaller than thefirst angle, e.g., relative to the line 1030 oriented perpendicular tothe intended direction 1020 of tape travel. As illustrated in FIG. 10B,the axes 1012, 1013 of the arrays 1006, 1008 are oriented aboutperpendicular to the intended direction 1020 of tape travel. Thusaccording to one embodiment, the second position may be characterized bythe axes 1012, 1013 of the arrays 1006, 1008 being aligned aboutperpendicular to the intended direction 1020 of tape travel thereacross,e.g., the second angle is about 0 degrees.

However, according to a further embodiment, the modules 1002, 1004 maybe selectively orientable between a first position, a second position,and/or a third position. Depending on the desired embodiment, the thirdposition may correspond to a third angle that may be greater than thefirst angle (e.g., see FIG. 10C), or less than the second angle (e.g.,see FIG. 11). Thus, in various embodiments, the modules may bepositioned in a clock-wise or a counter clock-wise direction relative tothe line 1030 depending on the direction the tape is moving, as willsoon become apparent.

Referring now to FIG. 10C, the axes 1012, 1013 of the arrays 1006, 1008are illustrated as being oriented at about a third position. Asmentioned above, according to one embodiment, the third position maycorrespond to a third angle β that has a value greater than that of thefirst angle φ. Thus, depending on the value of the first angle, thethird angle β may be between about 0.5° and about 15°, but may be higheror lower depending on the desired embodiment.

As illustrated in FIG. 10C, by orienting the axes 1012, 1013 of thearrays 1006, 1008 at a third angle β larger than that of the first angle(e.g., φ as shown in FIG. 10A), different transducer pairs align witheach other along the intended direction 1020 of tape travel. Accordingto one embodiment, N−1 of the N+1 transducers 1010 of the first array1006 may be about aligned with N−1 of the N+1 transducers 1010 of thesecond array 1008 when the axes 1012, 1013 of the arrays 1006, 1008 arepositioned towards the third position. However, depending on the angleat which the axes 1012, 1013 of the arrays 1006, 1008 are oriented whenpositioned at and/or towards a third position, different combinations oftransducers from each of the arrays may align with each other.

Furthermore, the N−1 of the N+1 transducers 1010 of the first and secondarrays 1006, 1008 are preferably aligned within the data tracks of atape (not shown) when positioned towards and/or at the third position.Thus, the N−1 of the N+1 transducers 1010 may preferably write to and/orread from N−1 corresponding data tracks of a magnetic tape (e.g., see902 and 906 of FIGS. 9A-9C).

The transducers 1010 of each array 1006, 1008 may also be positionedaccording to a logical numerical sequence. Looking to the embodimentillustrated in FIGS. 10A-10C, the transducers 1010 are numbered inascending, numerical order according to one embodiment. Although thelogical numerical sequence associated with the transducers 1010 of eachof the arrays 1006, 1008 is shown as beginning at the top end of both ofthe modules 1002, 1004 (e.g., the topmost transducer pair is labeled as“1”), according to other embodiments, the logical numerical sequence maybegin at the bottom of both of the modules. Moreover, according toanother embodiment, the logical numerical sequence may begin at the topend of one of the modules, while beginning at the bottom end of theother module, e.g., at opposite ends thereof.

Thus, as illustrated in FIG. 10A, when the axes 1012, 1013 of the arrays1006, 1008 are positioned towards the first position, the transducers1010 of the first array 1006 at even positions (e.g., represented byeven numbers next to the transducers 1010) in the numerical sequence areabout aligned with the transducers 1010 of the second array 1008 at oddpositions (e.g., represented by odd numbers next to the transducers1010) in the numerical sequence. As mentioned above, the numericalsequences of the transducers in the arrays 1006, 1008 are illustrated asstarting at a top of the modules 1002, 1004, but may alternatively startat a bottom of the modules 1002, 1004, or at opposite ends thereof, toachieve a similar result.

However, looking to FIG. 10B, the transducers 1010 of the first array1006 at even positions (e.g., represented by even numbers next to thetransducers 1010) in the numerical sequence may be about aligned withthe transducers 1010 of the second array 1008 at even positions (e.g.,represented by even numbers next to the transducers 1010) in thenumerical sequence when the axes of the arrays 1006, 1008 are positionedtowards the second position. Again, looking to FIG. 10B, when the arrays1006, 1008 are positioned towards the second position, each of the N+1transducers 1010 of each of the modules 1002, 1004 are about alignedwith each other.

Moreover, referring again to FIG. 10C, by positioning the axes 1012,1013 of the arrays 1006, 1008 at a third angle β larger than that of thefirst angle, the transducers 1010 of the first array 1006 at evenpositions (e.g., represented by even numbers next to the transducers1010) in the numerical sequence may be about aligned with thetransducers 1010 of the second array 1008 at even positions (e.g.,represented by even numbers next to the transducers 1010) in thenumerical sequence, different than the even positions of the first array1006. For example, which is in no way intended to limit the invention,looking to the first module 1002, the transducer pair at position 4 isaligned in the intended direction 1020 of tape travel, with thetransducer pair at position 2 of the second module 1004.

As the arrays 1006, 1008 are positioned between and/or at the first andsecond positions, the center to center pitch of the transducers 1010 aspresented to a tape varies as described above with reference to FIGS.9A-9C. With reference to the present description, the pitch as presentedto tape is measured perpendicularly to the intended direction 1020 oftape travel between imaginary parallel lines extending through the datatransducers along the intended direction 1020 of tape travel.

It follows that, according to one embodiment, when the axes 1012, 1013of the arrays 1006, 1008 are positioned at and/or towards the firstposition (e.g., see FIG. 10A), the transducers of the first array 1006and the transducers of the second array 1008 may be compatible with afirst data storage format, e.g., having a first center to center datatrack pitch. However, according to another embodiment, when the axes1012, 1013 of the arrays 1006, 1008 are positioned towards the secondposition (e.g., see FIG. 10B), the transducers of the first array 1006and the transducers of the second array 1008 may be compatible with asecond format, where the second format specifies a different center tocenter data track pitch than the first format. In other words, each ofthe first and second positions may correspond to a unique data storageformat, e.g., having a unique center to center data track pitch.

In view of the description above, the first format may specify Nconcurrently written and/or read data tracks, which preferablycorrespond to the N of the N+1 transducers 1010 of the first and secondarrays 1006, 1008 that are about aligned when the arrays 1006, 1008 arepositioned towards the first position, as illustrated in FIG. 10A.Furthermore, the second format may specify N+1 concurrently writtenand/or read data tracks as opposed to the N concurrently written and/orread data tracks of the first format. The N+1 concurrently writtenand/or read data tracks also preferably correspond to the N+1transducers 1010 of the first and second arrays 1006, 1008 that areabout aligned when the arrays 1006, 1008 are positioned towards thesecond position, However, according to another embodiment, the secondformat may specify N/2 concurrently-written and/or concurrently-readdata tracks. In various embodiments, N=2*M, wherein M is an integer,preferably in a range of 1 to 65.

Referring now to FIG. 10D, the apparatus 1000 may additionally include amechanism 1014, such as a tape dimensional instability compensationmechanism, for orienting the modules to control a transducer pitchpresented to a tape. The mechanism 1014 preferably allows for theorienting of the modules to be done while the modules are reading and/orwriting. According to various embodiments, the mechanism 1014 may be anyknown mechanism suitable for orienting the modules. Illustrativemechanisms 1014 include worm screws, voice coil actuators, thermalactuators, piezoelectric actuators, etc.

The apparatus 1000 is also depicted as including a controller 1016. Inone embodiment the controller 1016 may be configured to control themechanism 1014 based on a readback signal of the tape, e.g., servosignals, data signals, a combination of both, etc. According to anotherembodiment, the controller 1016 may be configured to control themechanism 1014 for orienting the modules 1002, 1004 based on a skew ofthe tape.

Furthermore, the controller 1016 may be configured to write data in aserpentine and/or non-serpentine fashion to a tape.

With continued reference to FIG. 10D, according to various embodiments,the dimensional conditions of the tape and/or orientation of the moduleswhen the tape was written may be retrieved e.g., from a database,cartridge memory, etc., and the orientation may be set based thereon toabout match the transducer pitch of the current operation to that of theprevious operation. Furthermore, additional logic, computer code,commands, etc., or combinations thereof, may be used to control themechanism 1014 for adjusting the orientation of the modules based on askew of the tape. Moreover, any of the embodiments described and/orsuggested herein may be combined with various functional methods,depending on the desired embodiment.

In one mode of use, when in a read only mode of operation with head thequasi-statically rotated or vertically oriented, and a reader becomesdysfunctional, then the head may index by 1, 2, or more positionscorresponding generally to the transducer pitch along the line 1030 thatis oriented orthogonal to the intended direction 1020 of tape travel,and still read the tape with all good readers. Accordingly, in oneembodiment, a controller may be configured to shift a position of thearray of transducers by one or more transducer pitches as measured inthe direction (along line 1030) perpendicular to the intended directionof tape travel when one of the operating transducers is dysfunctional,e.g., not operating correctly, has failed, has an erratic output orerror rate above a threshold, etc. As an example, referring to FIG. 10A,assume odd numbered transducers 1-15 of module 1004 are reading Mtracks, where N=2M, or 8 in this example. Assume transducer 3 becomesdysfunctional. Upon detecting the dysfunction, the controller shifts themodule such that the array shifts up by one position along line 1030,thereby aligning even transducers 2-16 over the tracks being read.

As mentioned above, although two modules 1002, 1004 are illustrated inFIGS. 10A-10D, in other embodiments, a system may include any number ofmodules e.g., at least two, at least three, at least four, a plurality,etc. depending on the desired embodiment. Referring to the illustrativeembodiment depicted in FIG. 11, which may be considered a modificationof apparatus 1000 of FIGS. 10A-10B, the apparatus 1100 shown may includea third module 1102 positioned between the first and second modules1002, 1004. Accordingly, various components of FIG. 11 may have commonnumbering with those of FIGS. 10A-10D.

Looking to FIG. 11, the apparatus 1100 includes modules having arrays oftransducers 1010. Moreover, as described above, the axes 1012, 1013,1104 of the arrays 1006, 1008, 1106 are preferably oriented aboutparallel to each other respectively, in addition to being fixed relativeto each other.

According to preferred embodiments, each of the N+1 transducers 1010 ofa given array 1006, 1008, 1106 are of the same type. In other words,each of the N+1 transducers 1010 of the first array 1006 are of the sametype, while the N+1 transducers 1010 of the second and third arrays1008, 1106 are of the same type. Moreover, depending on the desiredembodiment, the transducers of each of the arrays may be the same ordifferent as the transducers of the other arrays. Thus, in variousembodiments, the transducers 1010 of the first, second and/or thirdarrays 1006, 1008, 1106 may be readers and/or writers.

According to exemplary embodiments, the first second and/or thirdmodules 1002, 1004, 1102 may be used for data writing and/or datareading, depending on the desired embodiment. Thus, the apparatus 1100may serve as a write-read-write (WRW) device if the first and secondmodules 1002, 1004 are designed for at least data writing and the thirdmodule 1102 is designed for at least data reading. As an option, thefirst and second modules 1002, 1004 may be designed for data writing andnot for data reading, and/or the third module 1102 maybe designed fordata reading and not for data writing.

In another embodiment, the apparatus 1100 may serve as a read-write-read(RWR) device if the first and second modules 1002, 1004 are designed forat least data reading and optionally not for data writing, while thethird module 1102 is designed for at least data writing and optionallynot for data reading. However, this is in no way meant to limit theinvention; according to various other embodiments, a third, fourth,fifth, etc. module may be positioned with any orientation relative toother modules of the system, depending on the desired embodiment.

With continued reference to FIG. 11, the axes 1012, 1013, 1104 of thearrays 1006, 1008, 1106 may be positionable towards a third position,according to one embodiment. As illustrated, the third position may becharacterized by the axes 1012, 1013, 1104 of the arrays 1006, 1008,1106 each being oriented at a third angle ˜φ, relative to the line 1030oriented perpendicular to the intended direction 1020 of tape travel,e.g., thereby having a negative value. According to various embodiments,when the axes 1012, 1013, 1104 are positioned in and or towards thethird position, the third angle −φ may be between about −0.1° and about−10°, but may be higher or lower depending on the desired embodiment.However, when the axes 1012, 1013, 1104 of the arrays 1006, 1008, 1106are positioned towards and/or at the third position, the axes 1012,1013, 1104 of the arrays 1006, 1008, 1106 are each oriented at a thirdangle having a greater absolute value than the first angle φ, but thethird angle may be the same and/or smaller than the first angle in someembodiments.

As described above, the transducers 1010 of each array 1006, 1008, 1106may be positioned according to a logical numerical sequence. Referringstill to the embodiment illustrated in FIG. 11, the transducers 1010 maybe numbered in ascending, numerical order according to one embodiment.In a further embodiment, the logical numerical sequence associated withthe transducers 1010 of each of the array 1006, 1106, 1008 may begin atthe top end of both of all three of the modules 1002, 1004, 1104 (e.g.,the topmost transducer may be labeled as “1” as illustrated in FIGS.10A-10B). However, in other embodiments, the logical numerical sequencemay begin at the bottom of all three of the modules 1002, 1004, 1104 ofFIG. 11, and/or combinations thereof. For example, the logical numericalsequence may begin at the top end of two of the modules, while beginningat the bottom end of the other module, e.g., at opposite ends thereof.

Thus, when the axes 1012, 1013, 1104 of the arrays 1006, 1008, 1106 arepositioned towards a third position, N−1 of the N+1 transducers of thefirst array 1006 may be about aligned with N−1 of the N+1 transducers ofthe second array 1008. Additionally, when positioned towards the thirdposition, N of the N+1 transducers 1010 of the first array 1006 may beabout aligned with N of the N+1 transducers 1010 of the third array1106, i.e., the adjacent array. Furthermore, N of the N+1 transducers1010 of the third array 1106 may be about aligned with N of the N+1transducers 1010 of the second array 1008.

Depending on the desired embodiment, the transducers of the first,second and/or third modules may be used in conjunction with each other,e.g., by incorporating a controller as illustrated in FIG. 10D. However,depending on the configuration of modules used in combination, adifferent number of transducers thereon may be used to read from and/orwrite to data tracks on the tape.

In various embodiments, the transducers 1010 of the arrays 1006, 1008,1106 may preferably have a RWR configuration to conduct non-serpentinewriting. A RWR configuration allows the same writer array to write eachadjoining data track, despite reversal of the tape direction and/ororientation of the arrays 1006, 1008, 1106 while writing thereto. Thismay reduce writing errors, readback errors, data loss, etc., as well asreducing the misregistration budgeting requirements, as only one set oftrack tolerances comes into play. Moreover, using the same writer arrayto write adjoining data tracks ensures consistency while writing (e.g.,by enabling symmetrical servo pattern reading), overall higher arealdensity, etc.

Thus, as illustrated in the representational diagram of FIG. 12A, whichis in no way intended to limit the invention, the angles of orientationof the magnetic transitions on the tape 902 may be different such thatthe magnetic transitions written in the shingled data tracks 1202 in onedirection are at a different angle than the magnetic transitions inshingled data tracks 1204 written in the opposite direction. Moreover,when reading a data track, the reader array may be oriented to aboutmatch the angle of the written transitions of each shingled data trackto read the data thereon. Thus, if the reader array drifts over one ofthe adjacent data tracks, the off-track reading rejection SNR is higher,because the angle of orientation of the magnetic transitions on theadjacent data track will not match the angle of orientation of the readarray.

Note that, while not ideal, a WRW configuration could be used fornon-serpentine writing in some embodiments. In such embodiments, it ispreferable that, while writing data to adjoining data tracks, especiallyshingled data tracks, the same writer array is used for the adjoiningdata tracks. Moreover, similar to the description presented immediatelyabove, different writer arrays are not typically identical, as they havedifferent alignment characteristics, and therefore write datadifferently. For example, the write transducers of one writer array maynot have the same pitch, spacing, etc. as the write transducers ofanother writer array. Thus, using multiple writer arrays to write datato adjoining data tracks may result in readback errors, as the datawritten to the tracks may be aligned differently on each pass. Accordingto another example, using different writer arrays may result inoverwriting data on an adjoining track, thereby causing data loss.

Referring again to FIG. 11, as mentioned above, according to anotherillustrative embodiment, the transducers 1010 of the arrays 1006, 1008,1106 may have a WRW configuration (e.g., the data transducers 1010 ofthe first and second arrays 1006, 1008 may include writers, wherein thedata transducers of the third array 1106 may include readers), e.g.,which is a preferable configuration when conducting serpentine writing.While writing data with a WRW configuration, the leading writer andreader are preferably active, while the trailing writer is not active,depending on the intended direction 1020 of tape travel. As a result,the leading writer array may be used to write adjoining data tracks forone direction 1020 of tape travel, while the trailing writer array maybe used to write adjoining data tracks for the opposite direction oftape travel.

Thus, as illustrated in the representational diagram of FIG. 12B, whichis in no way intended to limit the invention, the angles of orientationof the magnetic transitions on the tape 902 may be about the same forshingled data tracks 1202 written in a first direction of tape travel,but different than the angles of orientation of the magnetic transitionsin the shingled data tracks 1204 written during the opposite directionof tape travel. This preferably reduces writing errors, readback errors,data loss, etc. and ensures consistency while writing, e.g., by enablingsymmetrical servo pattern reading.

According to yet another embodiment, the arrays 1006, 1008, 1106 mayhave a RWR configuration as described above, for conducting serpentinewriting. While writing data with a RWR configuration, the writer andcorresponding trailing reader may preferably be active, while theleading reader is not active, depending on the direction 1020 of tapetravel. As a result, the same writer may be used to write each adjoiningdata track for both directions of tape travel, despite reversal thereofwhile writing.

It will be clear that the various features of the foregoing systemsand/or methodologies may be combined in any way, creating a plurality ofcombinations from the descriptions presented above.

As will be appreciated by one skilled in the art, aspects of the presentinvention may be embodied as a system, method or computer programproduct. Accordingly, aspects of the present invention may take the formof an entirely hardware embodiment, an entirely software embodiment(including firmware, resident software, micro-code, etc.) or anembodiment combining software and hardware aspects that may allgenerally be referred to herein as “logic,” a “circuit,” “module,” or“system.” Furthermore, aspects of the present invention may take theform of a computer program product embodied in one or more computerreadable medium(s) having computer readable program code embodiedthereon.

Any combination of one or more computer readable medium(s) may beutilized. The computer readable medium may be a computer readable signalmedium or a non-transitory computer readable storage medium. A computerreadable storage medium may be, for example, but not limited to, anelectronic, magnetic, optical, electromagnetic, infrared, orsemiconductor system, apparatus, or device, or any suitable combinationof the foregoing. More specific examples (a non-exhaustive list) of thenon-transitory computer readable storage medium include the following: aportable computer diskette, a hard disk, a random access memory (RAM), aread-only memory (ROM), an erasable programmable read-only memory (EPROMor Flash memory), a portable compact disc read-only memory (e.g.,CD-ROM), a Blu-ray disc read-only memory (BD-ROM), an optical storagedevice, a magnetic storage device, or any suitable combination of theforegoing. In the context of this document, a non-transitory computerreadable storage medium may be any tangible medium that is capable ofcontaining, or storing a program or application for use by or inconnection with an instruction execution system, apparatus, or device.

A computer readable signal medium may include a propagated data signalwith computer readable program code embodied therein, for example, inbaseband or as part of a carrier wave. Such a propagated signal may takeany of a variety of forms, including, but not limited to,electro-magnetic, optical, or any suitable combination thereof. Acomputer readable signal medium may be any computer readable medium thatis not a non-transitory computer readable storage medium and that cancommunicate, propagate, or transport a program for use by or inconnection with an instruction execution system, apparatus, or device,such as an electrical connection having one or more wires, an opticalfibre, etc.

Program code embodied on a computer readable medium may be transmittedusing any appropriate medium, including but not limited to wireless,wireline, optical fibre cable, RF, etc., or any suitable combination ofthe foregoing.

Computer program code for carrying out operations for aspects of thepresent invention may be written in any combination of one or moreprogramming languages, including an object oriented programming languagesuch as Java, Smalltalk, C++ or the like and conventional proceduralprogramming languages, such as the “C” programming language or similarprogramming languages. The program code may execute entirely on theuser's computer, partly on the user's computer, as a stand-alonesoftware package, partly on the user's computer and partly on a remotecomputer or entirely on the remote computer or server. In the latterscenario, the remote computer may be connected to the user's computerthrough any type of network, including a local area network (LAN) or awide area network (WAN), or the connection may be made to an externalcomputer, for example through the Internet using an Internet ServiceProvider (ISP).

Aspects of the present invention are described herein with reference toflowchart illustrations and/or block diagrams of methods, apparatus(systems) and computer program products according to embodiments of theinvention. It will be understood that each block of the flowchartillustrations and/or block diagrams, and combinations of blocks in theflowchart illustrations and/or block diagrams, can be implemented bycomputer program instructions. These computer program instructions maybe provided to a processor of a general purpose computer, specialpurpose computer, or other programmable data processing apparatus toproduce a machine, such that the instructions, which execute via theprocessor of the computer or other programmable data processingapparatus, create means for implementing the functions/acts specified inthe flowchart and/or block diagram block or blocks.

These computer program instructions may also be stored in a computerreadable medium that can direct a computer, other programmable dataprocessing apparatus, or other devices to function in a particularmanner, such that the instructions stored in the computer readablemedium produce an article of manufacture including instructions whichimplement the function/act specified in the flowchart and/or blockdiagram block or blocks.

The computer program instructions may also be loaded onto a computer,other programmable data processing apparatus, or other devices to causea series of operational steps to be performed on the computer, otherprogrammable apparatus or other devices to produce a computerimplemented process such that the instructions which execute on thecomputer or other programmable apparatus provide processes forimplementing the functions/acts specified in the flowchart(s) and/orblock diagram block or blocks.

It will be further appreciated that embodiments of the present inventionmay be provided in the form of a service deployed on behalf of acustomer.

While various embodiments have been described above, it should beunderstood that they have been presented by way of example only, and notlimitation. Thus, the breadth and scope of an embodiment of the presentinvention should not be limited by any of the above-described exemplaryembodiments, but should be defined only in accordance with the followingclaims and their equivalents.

What is claimed is:
 1. An apparatus, comprising: at least two modules,each of the modules having an array of N+1 transducers, wherein an axisof each array is defined between opposite ends thereof, wherein the axesof the arrays are oriented about parallel to each other, wherein no morethan N of the N+1 transducers of a first array of a first of the modulesare about aligned with N of the N+1 transducers of a second array of asecond of the modules when the axes of the arrays are positioned towardsa first position, the first position being characterized by the axes ofthe arrays each being oriented at a first angle between about 0.1° andabout 10° relative to a line oriented perpendicular to an intendeddirection of tape travel thereacross, wherein N+1 of the N+1 transducersof the first array are about aligned with N+1 of the N+1 transducers ofthe second array when the axes of the arrays are positioned towards asecond position, the axes of the arrays each being oriented at a secondangle that is smaller than the first angle relative to the line orientedperpendicular to the intended direction of tape travel.
 2. An apparatusas recited in claim 1, wherein the transducers of the first array andthe transducers of the second array are compatible with a first formatwhen the axes of the arrays are positioned towards the first position,the first format specifying N concurrently-written and/orconcurrently-read data tracks, wherein the transducers of the firstarray and the transducers of the second array are compatible with asecond format when the axes of the arrays are positioned towards thesecond position, the second format specifying a different track pitchthan the first format.
 3. An apparatus as recited in claim 2, whereinthe second format specifies N/2 concurrently-written and/orconcurrently-read data tracks, where N=2*M, wherein M is an integer. 4.An apparatus as recited in claim 1, where N=2*M, wherein M is aninteger.
 5. An apparatus as recited in claim 1, further comprising acontroller configured to shift the array of transducers by one or moretransducer pitches in a direction perpendicular to the intendeddirection of tape travel when one of the operating transducers isdysfunctional.
 6. An apparatus as recited in claim 1, wherein thetransducers of the first array are reader/writer pairs, wherein thetransducers of the second array are reader/writer pairs.
 7. An apparatusas recited in claim 1, wherein the second position is characterized bythe axes of the arrays being aligned about perpendicular to the intendeddirection of tape travel thereacross.
 8. An apparatus as recited inclaim 1, further comprising a controller configured to write data in anon-serpentine fashion using the apparatus.
 9. An apparatus as recitedin claim 1, further comprising a controller configured to write data ina serpentine fashion using the apparatus.
 10. An apparatus as recited inclaim 1, further comprising a mechanism for orienting the modules tocontrol a transducer pitch presented to a tape.
 11. An apparatus asrecited in claim 10, further comprising a controller configured tocontrol the mechanism for orienting the modules based on a skew of thetape.
 12. An apparatus as recited in claim 1, wherein the apparatus isconfigured to read and/or write with the N+1 transducers when the axesof the arrays are positioned towards the second position.
 13. Anapparatus as recited in claim 1, wherein the transducers of each arrayare positioned according to a logical numerical sequence, wherein thetransducers of the first array at even positions in the numericalsequence are about aligned with the transducers of the second array atodd positions in the numerical sequence when the axes of the arrays arepositioned towards the first position.
 14. An apparatus as recited inclaim 1, wherein the transducers of each array are positioned accordingto a logical numerical sequence, wherein the transducers of the firstarray at even positions in the numerical sequence are about aligned withthe transducers of the second array at even positions in the numericalsequence when the axes of the arrays are positioned towards the secondposition.
 15. An apparatus as recited in claim 1, wherein the axes ofthe arrays are positionable towards a third position, the third positionbeing characterized by the axes of the arrays each being oriented at athird angle between about −0.1° and about −10° relative to the lineoriented perpendicular to the intended direction of tape travel when theaxes are in the third position.
 16. An apparatus as recited in claim 15,wherein at least three modules are present.
 17. An apparatus as recitedin claim 1, wherein N−1 of the N+1 transducers of the first array areabout aligned with N−1 of the N+1 transducers of the second array whenthe axes of the arrays are positioned towards a third position, thethird position being characterized by the axes of the arrays each beingoriented at a third angle greater than the first angle.
 18. An apparatusas recited in claim 1, further comprising: a drive mechanism for passinga magnetic medium over the modules; and a controller electricallycoupled to the modules.